But on Wednesday night Mischa Barton sparked rumours she is engaged to boyfriend Sebastian Knapp as she was spotted wearing a huge diamond ring.

The 26-year-old actress debuted the jewel as she arrived for the afterparty following the official opening night of Steel Magnolias at Harry's Bar in Dublin, Ireland.

Something to tell us? Mischa Barton was seen wearing what appeared to be an engagement ring as she headed out in Dublin, Ireland, on Wednesday night

Sparkler: Mischa wore the jewel on her ring finger

Mischa appeared happy to show off her new accessory, smiling for waiting photographers as she made her way inside.

The former O.C. actress wore a loose-fitting jumper with black skinny jeans and brown boots, accessorising her outfit with a colourful scarf.

Mischa and 28 Days Later actor Sebastian went public with their relationship in July, just a matter of weeks after the actress spoke about her self-imposed man ban.

The pretty brunette - who has previously dated the likes of oil heir Brandon Davis and The Kooks frontman Luke Pritchard - said: 'I've given up men. Sadly, there
doesn't seem to be anyone out there for me,' she told the Mail. 'My last
three boyfriends haven't worked out, so I'm giving guys a rest for a
while.

'I'm putting
all my love, care and attention into my three dogs. Don't ask why, but
they are a good replacement for men in terms of affection.'

From strength to strength: Mischa and Sebastian have been dating since July

However, Mischa and Sebastian's relationship appears to have gone from strength to strength since they started dating, with the actor even supporting his girlfriend at her recent store launch.

She said: 'He's great. I was like, "You don't have to come to the store opening, you don't have to do anything. But he said, "No I'm coming to support you."

'We met at Ashley Madekwe's wedding. She's an actress I've worked with a lot.'

A spokesperson for Mischa commented on the piece of jewellery, saying: 'Mischa was wearing the ring as wardrobe for the opening night of her play.'

Dressed down: Mischa wore a loose-fitting jumper and skinny black jeans with boots as she attended the afterparty of the opening night of Steel Magnolias in Dublin